Kitu na Kosa la Ahadi katika JavaScript

Inakubalika zaika kwenye funkta reject kupitisha si mkondo wenye kosa, bali kitu chenye kosa:

javascriptlet promise = new Promise(function(resolve, reject) {
  setTimeout(function() {
    reject(new Error('kosa katika ahadi')); // kitu chenye kosa
  }, 3000);
});

Pia unaweza kutupa vitu vilivyo na makosa kwa kutumia throw - hii itakuwa sawa na kupitisha kwenye reject:

javascriptlet promise = new Promise(function(resolve, reject) {
  setTimeout(function() {
    throw new Error('kosa katika ahadi'); // sawa na reject
  }, 3000);
});

javascriptlet promise = new Promise(function(resolve, reject) {
  setTimeout(function() {
    let isError = false;
    
    if (!isError) {
      resolve('mafanikio');
    } else {
      reject('kosa');
    }
  }, 3000);
});